Chapter 13: Spirochetes
Terms
undefined, object
copy deck
- What are the three genera of spirochetes?
- Treponema, Borrelia, and Leptospira
- Treponema produces no toxins or tissue destructive enzymes – how does it cause disease?
- The host’s own immune responses – inflammatory cell infiltrates, proliferative vascular changes, and granuloma formation.
- Describe primary syphilis?
- Painless chancre that erupts at the site of inoculation up to 6 weeks after the initial contact – highly infectious. This resolves over the next 6 weeks.
- Describe secondary syphilis?
- Bacteremic stage occurs approx. 6 weeks after the chancre has healed. Systemic – widespread rash, lymphadenopathy, multi organ involvement. Also, conyloma latum – lesion occurs in warm, moist sites.
- What is latent syphilis?
- If gone untreated, features of secondary syphilis will resolve, but latency will continue for several years, often including relapses.
- Describe the three components of tertiary syphilis?
-
1. Gummatous syphilis – granulomatous lesions which eventually necrose
2. Cardiovascular syphilis – ie. aortic aneurism
3. Neurosyphilis – subacute meningitis (predominance of lymphocytes), meningovascular syphilis, tabes dorsalis, general paresis of the insane. Sometimes neurosyphilis is asymptomatic. - What is the Argyll-Robertson pupil?
- Like the prostitute with syphilis, it “accommodates but does not react.†Caused by the midbrain lesion in tabes dorsalis and general paresis.
- Rule of sixes in syphilis?
- See page 93
- What is the treatment of choice for syphilis?
- Penicillin – which can even cross the placenta and cure congenital syphilis.
- Describe Treponema pallidum subspecies pertenue?
- Yaws – a disease of the moist tropics – tertiary lesions can cause disfigurement of the face.
- Describe Treponema pallidum subspecies carateum?
- Pinta – skin disease limited to rural Latin America.
- What is the most commonly reported tick-borne illness in the US and what bug causes it?
- Lyme disease caused by Borrelia burgdorferi – Ixodes tick.
- Describe similarities between Lyme disease and syphilis?
-
Both are caused by spirochetes.
Both have a primary stage involving a single painless skin lesion.
Both involve spread throughout the body, with multiple organ involvement.
Both cause chronic problems years later. - What is the skin lesion of Lyme disease called?
- Erythema chronicum migrans.
- To which 4 organ systems do Borrelia spirochetes disseminate in early stages?
- Skin, nervous system, heart, and joints.
- What antibx are used to treat Lyme disease?
- Penicillin or doxycycline.
- What bug causes relapsing fever? How does it cause relapses?
- Borrelia recurrentis. Antigenic variation involves the rapid change of surface proteins, so the bug is unrecognizable by antibodies.
- Where can leptospira be found (reservoir)?
- Urine of dogs, rats, livestock, and wild animals.
- Describe the first leptospiremic phase?
- Invasion of blood and CSF, with fever, headache, muscle aches. Classical signs – red conjunctiva and photophobia.
- What is Weil’s disease? What causes it?
- Infectious jaundice caused by a Leptospira species.